public class Main {
    public static void main(String[] args) {
        // # @ @ @ #
        // @ * * * @
        // @ * * * @
        // @ * * * @
        // # @ @ @ #
        int n = 7;
        System.out.println(Math.pow(12, 2));
        for (int i = 1; i <= n; i++) {
            if (i == 1 || i == n) {
                for (int j = 1; j <= n; j ++) {
                    if (j == 1 || j == n) {
                        System.out.print(" #");
                    } else {
                        System.out.print(" @");
                    }
                }
            } else {
                for (int j = 1; j <= n; j ++) {
                    if (j == 1 || j == n) {
                        System.out.print(" @");
                    } else {
                        System.out.print(" *");
                    }
                }
            }
            System.out.println();
        }
    }
}